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Kepler-78b is a planet that shouldn’t exist. This scorching lava world circles its star every eight and a half hours at a distance of less than one million miles — one of the tightest known orbits. According to current theories of planet formation, it couldn’t have formed so close to its star, nor could it have moved there.

Kepler-78b is a planet that shouldn’t exist. This scorching lava world, shown here in an artist’s conception, circles its star every eight and a half hours at a distance of less than one million miles. According to current theories of planet formation, it couldn’t have formed so close to its star, nor could it have moved there. (Credit: David A. Aguilar (CfA))

“This planet is a complete mystery,” says astronomer David Latham of the Harvard-Smithsonian Center for Astrophysics (CfA). “We don’t know how it formed or how it got to where it is today. What we do know is that it’s not going to last forever.”

“Kepler-78b is going to end up in the star very soon, astronomically speaking,” agrees CfA astronomer Dimitar Sasselov.

Not only is Kepler-78b a mystery world, it is the first known Earth-sized planet with an Earth-like density. Kepler-78b is about 20 percent larger than Earth, with a diameter of 9,200 miles, and weighs almost twice as much. As a result it has a density similar to Earth’s, which suggests an Earth-like composition of iron and rock.

Feb. 28, 2013 — NASA’s Van Allen Probes mission has discovered a previously unknown third radiation belt around Earth, revealing the existence of unexpected structures and processes within these hazardous regions of space.

Two giant swaths of radiation, known as the Van Allen Belts, surrounding Earth were discovered in 1958. In 2012, observations from the Van Allen Probes showed that a third belt can sometimes appear. The radiation is shown here in yellow, with green representing the spaces between the belts. (Credit: NASA/Van Allen Probes/Goddard Space Flight Center)

The belts, named for their discoverer, James Van Allen, are critical regions for modern society, which is dependent on many space-based technologies. The Van Allen belts are affected by solar storms and space weather and can swell dramatically. When this occurs, they can pose dangers to communications and GPS satellites, as well as humans in space.

On August 31, 2012 a long filament of solar material that had been hovering in the sun’s atmosphere, the corona, erupted out into space at 4:36 p.m. EDT. The coronal mass ejection, or CME, traveled at over 900 miles per second. The CME did not travel directly toward Earth, but did connect with Earth’s magnetic environment, or magnetosphere, causing aurora to appear on the night of Monday, September 3.

The image above includes an image of Earth to show the size of the CME compared to the size of Earth.

This artist’s conception shows the inner four planets of the Gliese 581 system and their host star. The large planet in the foreground is Gliese 581g, which is in the middle of the star’s habitable zone and is only two to three times as massive as Earth. Some researchers aren’t convinced Gliese 581g exists, however.
CREDIT: Lynette Cook

The controversial exoplanet Gliese 581g is the best candidate to host life beyond our own solar system, according to a new ranking of potentially habitable alien worlds.

Gliese 581g shot to the top of the list — which was published Thursday (July 19) by researchers at the University of Puerto Rico at Arecibo’s Planetary Habitability Laboratory (PHL) — after a new study marshaled support for its long-debated existence.

The exoplanet was discovered in September 2010, but other astronomers began casting doubt on its existence just weeks later. Now Gliese 581g’s discoverers have rebutted their critics’ charges in a new paper, and have done so effectively enough to get the PHL onboard.

Even if they can be a major disaster for people nearby them, volcanoes do one good thing: helping to cool the planet by sending sun-reflecting chemicals into the stratosphere. Now two Harvard engineers are trying to replicate the better part of the volcanic process on a small scale by spraying thousands of tons of sulfate aerosols into the atmosphere above New Mexico.

Understanding how the mantle flows is a major interest for geophysics because it could help to explain earthquakes or volcanic eruptions. Computers can model it, but how can scientists be sure they are correct?

The Air Force’s X-37B–its secret robotic space plane that’s been orbiting the Earth on a mission shrouded in mystery for more than a year–landed safely in the wee hours Saturday morning at Vandenberg Air Force Base in California. Orbital Test Vehicle 2 (OTV-2) is the second X-37B test vehicle to successfully complete an orbital mission and autonomously return to Earth, following sister spacecraft OTV-1’s 225-day mission in 2010.